The Men's Nano Puff Pullover by Patagonia is wind- and water-resistant, the Nano Puff Pullover is incredibly lightweight, highly compressible insulation and can be worn as a midlayer or outerwear in cold climates. Already a cult classic with Patagonia's ambassadors and testers, the Nano earns unanimous raves for versatility, surprising warmth and terrific all-around performance in a superlight, no-frills package.

It's weather-resistant enough to wear as an insulated shell in a wet snowstorm, trim enough to pull on for chilly rock pitches (and still see your footholds), and warm enough for light belay parka duty on quick alpine dashes. The wind-blocking, moisture-shedding DWR (durable water repellent) finished 100% all-recycled polyester shell (1-oz 15-denier) also glides effortlessly, whether worn as an outer or midlayer.

Low-bulk, hydrophobic, highly compressible PrimaLoft One (60 g) traps heat with remarkable efficiency, even when wet. The deep front zipper allows for easy ventilation. The Nano also packs down to practically nothing and stuffs into a single chest pocket that has a carabiner clip-in loop.

The Nano Puff by Patagonia is the perfect mid-weight alternative to a fleece or down. The best part of the Nano is that it will keep you warm, even if it gets wet,...Read complete review

The Nano Puff by Patagonia is the perfect mid-weight alternative to a fleece or down. The best part of the Nano is that it will keep you warm, even if it gets wet, the opposite of the effect of wet down.

It's very light, packs very small, and can be worn in place of a sweater to help block wind on cool days, or just throw on to warm up while outdoors. If you are looking for a very light, very compressible & warm, but not not, mid-layer, the Nano Puff is a great choice.

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Most Liked Negative Review

Big difference between Medium and Large

First of all, Im A HUGE fan of Patagonia products, I just have a HUGE problem with Patagonia sizing. There is such a tremendous difference between their mens size L and mens size...Read complete review

First of all, Im A HUGE fan of Patagonia products, I just have a HUGE problem with Patagonia sizing. There is such a tremendous difference between their mens size L and mens size M in all their newer products. The nano puff tag says it is a "slim fit". I'm a size 41 coat with 33 waist, i ordered a size L in the nano puff pullover and it swallowed me whole. I went back to the store to try and exchange for a size M, and it was way too tight. It just seems like Patagonia is like alot of other clothing makers, in that they skip a size...size M is 38-40, where size L is 42-44...this leaves me hangin out to dry. Love the quality, feel, and look of the product. Just wish there wasn't such a huge sizing gap between size L and size M.

Thin but still very warm, the Nano is my go-to midlayer under a shell for constantly changing Northeast mountain conditions. The shell is durable, with quality zippers and stitching. Nice touches like contrast stitching and taped seams where needed. Easily vented with the neck zipper up or down. Plus the chest pocket is a good place to put your phone so it doesn't get too cold and prematurely die (if you've left one in your shell pocket in cold weather, you know what I mean).

The nano puff is an excellent item in the gear closet. I have worn it as a layer in 32 degree snow under a thin rain shell and has kept me warm with only a t-shirt under it. I'm 5'9", 40" chest, around 180lbs, with broad shoulders, and the medium fits great. It is a littler fuller in the body, so if you are looking for a slimmer fit, be aware. (Though i think the fall 2013 lineup has been slimmed up in the body) Excellent jacket, classic styling, easily stuffs into its own chest pocket.

I have a 40" chest, 31" waist, and am 5'10". Medium fits perfect. This garment serves very well to provide extra warmth and protection from wind when you are at rest. It is sized perfectly to fit over base layers and any mid layers like fleece that you might be wearing when you are active. I can't imagine actually hiking in one of these as it has poor breathability but then again, that is not what it is designed for. Get yourself a fleece. Climbers use these as a belay sweater.

It easily packs down into its own pocket and takes up little space in a pack. The zipper is nice and long to provide ventilation and to make it easy to put on or take off. Don't see the point of the jacket version and think Patagonia got it right when they originally came out with just this version.

This is a great early-spring/late-fall layer by itself that keeps you warm with little weight or bulk penalty. It also shines as a midlayer when the temps really drop. Is it as warm as my down sweater? Not at all but I don't think it was ever meant to be. It's a great no-brainer garmet you can throw in your pack in case you may need it.

If I have one complaint, I didn't find this anywhere near "wind resistant." I usually run warm but I feel the wind's cold penetrating the Nano whenever it gets past 10 mph- which is quite often on the Eastern Shore.

I ordered a large, but it was too roomy in the chest/waist/shoulders. The medium is a perfect fit in most areas, but the sleeves of the large would be better and the length is a bit too croppy. The large length was better there too. I'm about 5'-11" 165-#, an endurance athlete w/ a lean/muscular build. I recommend Patagonia offer this in a slimmer/fitted style for athletes.

First of all, Im A HUGE fan of Patagonia products, I just have a HUGE problem with Patagonia sizing. There is such a tremendous difference between their mens size L and mens size M in all their newer products. The nano puff tag says it is a "slim fit". I'm a size 41 coat with 33 waist, i ordered a size L in the nano puff pullover and it swallowed me whole. I went back to the store to try and exchange for a size M, and it was way too tight. It just seems like Patagonia is like alot of other clothing makers, in that they skip a size...size M is 38-40, where size L is 42-44...this leaves me hangin out to dry. Love the quality, feel, and look of the product. Just wish there wasn't such a huge sizing gap between size L and size M.